Zigzag magnetic labyrinth arc muffler



Oct. 21, 1952 J, A FAVRE 2,615,109

ZIGZG MAGNETIC LABYRINTH ARC MUFFLER Filed Jan. 25, 1950 Inventor-JOHT-l A.1:a\/1^e f His Attorney Patented oct. 21,v 1952 UNIri-:DSTATES PATENT' TOFFICE .101m A. FenomeniHurra., mignrmoenf-,-'eral-Elec.tric Company, a. corporation. ot New yAimiitaoonJanuary-25, 191.50;` sommo. noa-ri f -The invention relatestoarcmuiiers, particular-- lyfcf atype suitable for suppressing the hashfrom the cooperating arc quenchers of .enclosed or semi-enclosed'circuit breaker-sor in other similar service where a severe arcnashresemblingan explosion must be' 'suppressedwithin a lrelativelysmall Aspace.

The principal object is to provide an improved nesting'type of doubleoffset or zigzag .corrugated magnetic labyrinthv arc muiiier capable of.estab--l lishl'ng magnetic attractionffor drawing the arc into la loopinside `a restricted arcequenching space',474 providingabrupt changesindirection of the 'zig-zag p'assageformed between. nesting zigzagmagnetic members so that any incandescent particles projected with thegases arey intercepted bylthedouble offset corrugated kmembers anddepositedy thereon, aswell-as providing aplurality of'heat-absorbingzigzag l.passages `spaced to .secure good turbulence and. scouring andhence rapid cooling or quenching of .the hot arc gases, allwithoutyunduly drawing the arc into the mufileror unduly restricting .theffio'wof the gases therethrough...

Another object is to providean improved arc muiiier unit` assemblyhaving 'a plurality of parallel tortuous'paths formed-by nesting doubleoffset zigzaglmagnetic plates. `of .sufficient mass and spacing'adjacentthe path of. the arc tolsuccesstullyiwithstandthe maxixnumarcing actionand insure eiclent heat absorption of several arcing, actionsiin 4closesuccession and with the nesting double-oifset zigzag corrugations of theplates serving to minimize buckling or warping thereof undermaximumarcing conditions.

`.Qtlfier objects and advantagesof the invention winappear in thefoiiowingfdescription of the accompanymg drawin'g'in which Fig. 'l is apartial front view voione pole rvof a semi-enclosed 'circuit breakerrhaving an arc quencher provided with anarc muler embodying theimprovements of the-*present invention; Fig. 2 is a sectional view ofthecircuit breaker pole shown in Fig. 1 along the sectioniine 2-2andshowing the. spaced operating relation ofr the arc muffler with respecttothe arc quencher whereinv the arc is drawn be tween'the. stationaryand-movable circuit breaker contacto;v and. Fig. 4v3 is .an .enlargedvperspective viewfshowing the. details of construction of 'aino'dication` of the. rimproved zigzag magnetic type of arc quencher ofthepresent invet'ion suitable 'for heavy current service.

.ffRferrng to Figs. l and 2,'the single vpole 'of semienclosedmulti-'slot circuit breaker indicated 'generallyby the referencecharacter I0 is sciame. (ci. coef-14m),

provided' with a pair of shunt yconnected. movable contact rarms rIIhaving contact facing-s- T22-operable .into and out of abuttingengagementwith the contact facings I3 of the cooperating station` arycontact members I4. The'movableswitch contacts I`I are'. carried bykcross arm I5 thatfalso carriesthe contacts of 'theo'ther poles ofthecir-v cuit breaker, not shown. and is. operated by `sui-ttableoperating mechanism, also not shown. "The arc-produmedv upon separation`of contact facings I3l `'is quenched inan -arc quencher I6 and-ftheflash lis suppressed? -by vthe rimproved 'magnetic labyrinth arc muiiierHof the present invention.

As shown, the two movable switch membersk II operate in parallel slots2| formed between arcquenching" barriers 22, 23 and' 2-'4 that are ofthe improved transverse slotted type more fully described and claimed-inthe patent application, .Serial No. 132,258,- -led December 1'0, 1949 byCharles Titus fand assigned vto the assignee of thev present invention'.Thus, the arc drawn between-the-:contact 'faces -I 2 and I 3 uponopening of the'circuit breaker is immediately brought into intimatecontact with the are-quenching barriers 22, v'23 and 2'4 vand subjectedto the arc-quenching action thereof which is materially-improvedby'theprovision `of the series Vof parallel intercommunicating vslots26, 21, 28 and 29 4in each of the barriers. fy The rimproved zigzagImagnetic labyrinth @arc muiiier -`I-`I of the'presentinverition servesto a'ttractfthearcs and to suppress the flashis'suing'*V from the slots2| when parallel arcs are drawn? thereinto interrupt the circuit. `Asshown inFig. 2,'-the arc muiiier ITis composed of a'plu'rality'of nestedzigzag magnetic -members 3| that are mountedin juxtaposition'along theedge 'of the arcrquencher plates 22, 23, and 24 tofform a pluraloffsetzigzag pathmagnetic labyrinth having'each zigzag path traversethe'pa-th of the arc in each s1ot2l; Each of the magnetizable members:3| isprovided with central ydoubleoffset zigzag corrugationsi32kprojecting laterally on opposite sides thereof andwith parallel 4poles33 and r34 that project beyond the zigzag'edges of the corrugatlons32 toform mounting lugs 35 as more clearly shownin'the perspective view ofFig. 3. .A pair of'sidebarriers 36 and 31 are formed of suitableinsulating material for abutting the zigzag edges of members 3i 'andprovided with a series of slots 38 inthe opposite edges thereof forreceiving the projecting lugs 35 therein so as to mount the magneticmembers 3| with the oppositely projecting corrugations 32 of adjacentmembers in par-r allel nested spaced-apart relation Von opposite sidesof the longitudinal axis of the zigzag passage formed therebetween andwith each zigzag passage laterally closed by the insulating sidebarriers 36 and 3l. As shown, each of the side barriers 36 and 31 isformed of two duplicate piecesof insulating material in order tofacilitate punching of the slots therein.

Upon the opening of the circuit breaker to establish parallel arcs inthe slots 2|, magnetic members 3| are magnetizable by the current in thearcs and due to the concentration of the magnetic mass resulting fromthe nesting of the oppositely projecting zigzag corrugations 32 providesuicient magnetic attraction for drawing the arcs into a loop inside theslots 2|, thereby elongating the arcs and facilitating the arcquenchingaction of the transversely slotted insulating barriers 22, 23 and 24. Atthe same time,

the plurality of nested spaced-apart zigzag magnetic members 3| aprovide a plurality of heat absorbing zigzag passages therebetweenspaced to provide good turbulence and scouring, and hence rapid coolingor quenching of the hot arc gases that are recived from the slots 2|.Any incandescent particles carried in the gases are intercepted by themembers 3| in their passage through the magnetic labyrinth and depositedthereon. The double offset zigzag corrugation of the members 3| alsoserves to minimize buckling or warping thereof under maximum arcngconditions. Hence, the improved nested zigzag magnetic labyrinth arcmuffler I1 is able to successfully withstand several arcing actions inclose succession.

The modified form of the invention shown in Fig. 3 is particularlyadapted for heavy current service wherein somewhat less concentratedmagnetic attraction and somewhat more restriction to gas ow is requiredof the magnetic labyrinth arc muller due to the increased loopselfexpanding action of the arcs carrying the heavier currents. Toreduce the magnetic attraction, a suitable number of the magneticmembers 3| may be removed from the muiler il at spaced intervals, thusleaving the remaining rmembers 3| in spaced-apart groups A, B, C, and D,as shown in Fig. 3. Then, in order to further restrict the passage ofthe arc gases through the enlarged passages in the muilier insulatingpins 40 are interposed to substantially close the spaces between thealigned groups of magnetic members 3| forming the labyrinth. Thus, withthe improved nested zigzag plural path magnetic labyrinth muiilermodified as shown in Fig. 3, the overall restriction to gas flow throughthe zigzag members is somewhat increased but without correspondinglydecreasing the insulation between the members. Furthermore, withthegpins 40 located adjacent the top of the enlarged passage between thegroups of magnetic members 3|, as shown, pockets for stagnant gas areprovided by the enlarged closed space between the groups so as to act asinsulators therebetween and also enable portions of the arc to bemomentarily vented therein while the main now of arc gases passesthrough the plural labyrinthine paths provided by the remainingspaced-apart groups of nested zigzag magnetic membersl 3|.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is: 'A

l. An arc muffler having in `combination a plurality of magneticmembers, each provided v. ith oiset zigzag corrugations projectinglaterally on opposite sides thereof, and insulating means for mountingthe members in juxtaposition with the oppositely projecting corrugationsof adjacent members in nested spaced-apart relation on opposite sides ofthe longitudinal axis of the zigzag passage formed therebetween toconcentrate the magnetic mass of the members for attracting the arc andto intercept particles projected with the arc gases into the zigzagpassage.

2. An arc muiller having in combination a plurality of magnetic members,each having parallel mounting lugs and offset zigzag corrugationsprojecting laterally on opposite sides thereof, and insulating sidebarriers abutting the zigzag edges of the corrugations and provided withslots for receiving the parallel lugs to mount the members injuxtaposition with the oppositely offset corrugations of adjacentmembers in nested spaced-apart relation on opposite sides oi' thelongitudinal axis of the zigzag passage formed therebetween toconcentrate the magnetic mass of the members for attracting the arc andto intercept particles projected with the arc gases into the zigzagpassage.

3. An arc muiler having in combination a plurality of magnetizableplates, each having central double offset zigzag corrugations projectinglaterally on opposite sides thereof and parallel poles projecting beyondthe zigzag edges of the corrugations to form mounting lugs, andinsulating side barriers abutting the zigzag edges yof the corrugationsand provided withslots forkregceiving the lugs to mount the members injuxtaposition with the oppositely projecting corrugations of adjacentmembers in parallel nested spaced-apart relation on opposite sides ofthe longitudinal axis of the zigzag passage formed therebetween toconcentrate the magnetic mass of the members for attracting the arc andto intercept particles projected with the arc gases into the zigzagpassage.

4. An arc Amufller having in combination plurality of magnetic plates,each having parallel poles at the ends thereof and central` doubleoilset zigzag corrugations projecting laterally on opposite sides of thepoles, and insulating means for mounting the plates with the poles njuxtaposition and with the oppositely projecting corrugations ofadjacent members in nested spacedapart relation on opposite sides of thelongitudinal axis of the zigzag passage formed therebetween toconcentrate the magnetic mass of the plates for attracting the arc andto intercept particles projected with the arc gases into the zigzagpassage. t y

5. An arc muiller having in combination a plurality of magnetizablemembers, each having double offset zigzag corrugations projectinglaterally on opposite sides thereof and parallel poles extending beyondthe zigzag edges of the corrugations to form mounting lugs, a pair oflinsulating side barriers in spaced apart parallel relation Vforabutting the zigzag edges of the corrugations and having slots forreceiving the lugs to mount the members in juxtaposition in spaced-apartgroups with the oppositely projecting corrugations of adjacent membersof each group in nested spaced-apart relation on opposite sides of thelongitudinal axis of the zigzagrv passage formed therebetween toconcentrate the magnetic mass'of the members for attracting the arc andto intercept particles projected with the arc gases into each passage,and insulating means closing the space between the groups to prevent thepassage of particles and arc gases therebetween.

le of this patent:

6 UNITED STATES PATENTS Number Name Date JOHN A- FAVRE- 2,293,513 LindeAug. 18, 1942 2,337,949 Walle Dec. 28, 1943 REFERENCES CITED 5 2,408,352Titus sept. 24, 1946 The following references are of record in the2,442,199 Dickinson May 25, 1948

